/Engine/Source/Runtime/Engine/Classes/Kismet/GameplayStatics.h
Returns the number of active player states, there is one player state for every connected player even if they are a remote client. Indexes up to this can be use as PlayerStateIndex parameters for other functions.
static int32 GetNumPlayerStates ( const [UObject](API\Runtime\CoreUObject\UObject\UObject) * WorldContextObject )